METHOD OF PRODUCING alpha , alpha -TREHALOSE

Abstract: The method for producing crystalline alpha , alpha -trehalose by isolation from baker's yeast consists in the extraction of baker's yeast with ethanol of concentration 70 to 96 volume %, vacuum concentration of the obtained extract to the concentration of alpha , alpha -trehalose 2 to 30 weight %, after removing the solid portion by filtration, and of the following membrane filtration process consisting of ultrafiltration through an ultrafiltration membrane with the separation limit of molecular masses higher than 500 and, if desirable, of the preceding microfiltration through a microfiltration membrane with the mean pore diameter ranging from 0.05 to 5 mu m, preferably from 0.05 to 0.15 mu m, where the obtained clear solution, after decolourizing with activated charcoal, is brought into contact with an ion exchanger in H<+> cycle and then with an ion exchanger in OH<-> cycle and the resulting demineralized solution is concentrated in vacuum to the concentration of 40 to 85 weight % and alpha , alpha -trehalose crystallizing, after addition or ethanol in the amount of 0.5 to 1.5 parts per part of alpha , alpha -trehalose, is isolated and recrystallized from ethanol after repeated demineralization. Another object of the method according to the invention consists in carrying out the continuous ultrafiltration through an ultrafiltration membrane with the separation limit of molecular masses higher than 500 and, if desirable, carrying out the preceding microfiltration through a microfiltration membrane with mean pore diameter ranging from 0.05 to 5 mu m, preferably from 0.05 to 0.15 mu m. In the method carried out according to the invention, a styrene-divinylbenzene copolymer with strongly acid sulfo groups is used as a cation exchanger and a styrene-divinylbenzene copolymer with quaternary dimethylhydroxyethylammonium exchanging groups as an anion exchanger. Disaccharide alpha , alpha -trehalose produced by the method according to the invention is an important raw material or intermediate in pharmacy, food industry and biochemial research.

Description: Description Method of Producing a,a-Trehalose Technical Field The invention pertains to the method for producing disaccharide α,α-trehalose (α-D-glucopyranosyl-α-D-glucopy- ranoside) , which is an important raw material or intermediate in food industry, pharmacy and biochemistry. Background Art α,α-Trehalose may be obtained by isolation from a broad selection of natural substances, above all from Selaginella lepidophyla by origin from southwest of USA which is now grown in the countries of Middle East. At the present time, the most suitable source of this disaccharide is baker's yeast, above all for its good accessibility, low price and a relatively high content of a ,α-trehalose. The isolation of α,α-trehalose from baker's yeast was described for the first time already in 1936 (K. Myrback, B. Ortenblad: Biochem. Z . 288, 329 (1936)) and its modified form (Z.C. Stewart, N.K. icht yer, C.S. Hudson: J.Am.Cheia. Soc . 72, 2059 (1950)) is employed for the preparation of α,α-treh- alose up to the present time. A substantial disadvantage of these procedures, which limits above all their industrial application, consists in the method of deproteinization by addition of an aqueous solution of zinc sulfate to the concentrated ethanolic extract of yeast followed by precipitation of sulfate anions with a solution of barium hydroxide. This method of deprotei¬ nization puts high demands on purification of the product, where the required high purity is due to the pharmaceutical and nutrition applications. The method also produces conside- rable amounts of solid inorganic wastes, the liquidation of which has high financial demands on investment, energy and raw materials. Disclosure of Invention The above mentioned disadvantages are avoided in a great deal in the method of producing α,α-trehalose according to the present invention, where the procedure based on modern membrane processes is marked by a high quality of the product, low investment cost, low environmental load, accessible raw materials and a relatively high yield. The object of the present invention is a method for producing crystalline α,α-trehalose by isolation from baker's yeast, which method consists in the extraction of baker's yeast with ethanol of concentration 70 to 96 volume %, vacuum concentration of the obtained extract to the content of α,α-trehalose 2 to 30 weight %, after removing the solid portion by filtration, and in the following membrane filtra¬ tion process consisting of ultrafiltration through an ultrafiltration membrane with the separation limit of molecular masses higher than 500 and, if desirable, of the preceding microfiltration through a microfiltration membrane with the mean pore diameter ranging from 0.05 to 5 μm, preferably from 0.05 to 0.15 μ , where the obtained clear solution, after decolourizing with activated charcoal, is brought into contact with an ion exchanger in H + cycle and then with an ion exchanger in OH " cycle and the resulting demineralized solution is evaporated in vacuum to the concentration of 40 to 85 weight % and α,α-trehalose, crystallizing after addition of ethanol in the amount of 0.5 to 1.5 parts per 1 part of a,α-trehalose, is isolated and recrystaUized from ethanol after repeated demineralization. Another object of the method according to the inventa- tion consists in the fact that the continuous ultrafiltration is carried out through an ultrafiltration membrane with the separation limit of molecular masses higher than 500 and, if desirable, the preceding microfiltration is carried out through a microfiltration membrane with mean pore diameter ranging from 0.05 to 5 μm, preferably from 0.05 to 0.15 μm. In the method carried out according to the invention, it is advantageous to use a styrene-divinylbenzene copolymer with strongly acid sulfo groups as a cation exchanger and a styrene- divinylbenzene copolymer with quaternary dimethy- lhydroxyethyl- ammonium exchanging groups as an anion exchanger. The method according to the invention may be realized in such a way, that baker's yeast is extracted at ambient tempe¬ rature with 96% ethanol denatured with 2-propanol, the extracted yeast is filtered off and ethanol is removed from the filtrate by vacuum distillation. The obtained aqueous or water- ethanolic solution with the concentration of α,α-treh¬ alose 10 to 40 weight % is subjected to ultrafiltration through an ultrafiltration membrane with the separation limit of molar masses higher than 500, or may be first subjected to microfiltration through a microfiltration membrane with the mean pore diameter ranging from 0.05 to 5 μm and then to ultrafiltration through an ultrafiltration membrane with the separation limit of molar masses higher than 500. The clear aqueous solution after decolourizing with activated charcoal is deionized on the columns of cation exchanger and anion exchanger and concentrated in a vacuum evaporator to aqeous syrup with the concentration of α,α-trehalose 50 to 70 weight %. After addition of ethanol to the syrup in the amount of about 1 part per 1 part of α,α-trehalose, the disaccharide crystallizes at normal or suppressed temperature. Crystalline a,α-trehalose is isolated by filtration and dried at 40 to 60°C at reduced presure. If crystalline α,α-trehalose of purity higher than 99 weight % is produced, the crude substance has to be recrystaUized from ethanol after deionization realized in a similar way. The method according to the invention renders α,α-tre¬ halose of high quality in a satisfactory yield, thus enabling its further direct use, e.g., in pharmacy or in food produc¬ tion. Besides extracted yeast, which can be further utilized, especially for the isolation of ergosterol, no important wastes are produced, which means that this technology has substatially lower impact on environment than the nowadays used production technologies of α,α-trehalose. This fact has also the positive effect in lower investment and operation cost of the production according to the present invention. Examples Example 1 Baker's yeast (1000 g) is extracted under intense stirring at ambient temperature with 3000 ml 96 % ethanol denatured with 6 % 2-propanol for 45 min. The suspension is filtered and the filtration cake is washed with 250 ml ethanol and is further used for the isolation of ergosterol. The resulting filtrate is concentrated in a vacuum evaporator (20 mm Hg, bath temperature 60°C) to the volume of 400 ml and transferred into a filtration cell of capacity 450 ml provided with an efficient stirring of filtered liquid and microfiltration membrane Synpor" with the mean pore diameter 0.12 μm. Overpressure 0.08 MPa is exerted above the filtered liquid and membrane by nitrogen introduced from a pressure cylinder and 380 ml liquid is filtered. This filtrate is subjected to ultrafiltration in the same cell provided with an ultrafiltratiom membrane from polysulfone having the separation limit of molecular masses 20,000. In this operati¬ on, overpressure above the filtered liquid and membrane is 0.25 MPa and 360 ml filtrate is obtained. Clear aqueous solution (360 ml) is decolourized by addition of 10 g activated charcoal, which is then filtered off, and the filtrate is deionized in a column of 300 ml Wofatit KPS in H + cycle and a column of 215 ml Wofatit SBK in OH " cycle. The ion exchangers are washed with 1500 ml water and the combined solutions are evaporated in vacuum (20 mm Hg) to aqeous syrup containing 71 weight % α, -trehalose. After addition of 50 ml ethanol, crystallization proceeds at ambient temperature for 16 hours. Crystalline α,α-trehalose is isolated by filtration of a fritted-glass filter G-2, the filtration cake is washed with 50 ml ethanol and dried in vacuum (50°C, 15 mm Hg) giving 31.5 g crystalline α,α-trehal¬ ose of purity 97.1 %. Another 2.7 g of the crystalline product is obtained by concentrating mother liquors and crystallization under above specified conditions. Example 2 Dried baker's yeast (250 g) is mixed at laboratory temperature with 580 ml demineralized water to a paste which is then extracted with 2000 ml 96 % ethanol denatured with 7 % 2-propanol for 30 minutes. The suspension is filtered and the filtration cake is washed with 2150 ml of 70 % ethanol denatured with 2-propanol. The filtrate obtained is concen¬ trated in a vacuum evaporator (20 mm Hg, temperature of water bath 60°C) to the volume of 400 ml, transferred into filtra- tion cell of capacity 450 ml with the continuous flow of filtered liquid over a membrane and with the ultrafiltration membrane from cellulose acetate having the separation limit of molecular masses 5000. An overpressure 0.2 MPa is exerted above the filtered liquid and 350 ml filtered solution is collected, decolourized with 13 g activated charcoal, which is then filtered off, and deionized on a column of 280 ml Wofatit KPS in H + cycle and by addition 250 ml Wofatit SBK in OH " cycle (pH of the deionized solution is 4.2). The combined solutions, after removing the anion exchanger by filtration and washing both ion exchangers with 900 ml water, are evaporated in vacuum to an aqueous syrup with concentration of ,α-trehalose 79 weight %. Crystallization proceeds after addition of 80 ml ethanol at 5°C for 12 hours. Filtration and washing the filtration cake with 40 ml ethanol gives 42.1 g crude α,α-trehalose of purity 98.2 %, which is dried at laboratory temperature. Another 3.2 g product is obtained by concentrating mother liquors and crystallization carried out under above specified conditions. Crude crystalline ,α-trehalose (45.3 g) is dissolved in 190 ml demineralized water at 40°C and deionization is carried out on the column containing 5 ml Wofatit KPS in H + cycle and 10 ml Wofatit SBK in OH " cycle. The resulting deionized solution is evaporated in vacuum (20 mm Hg) to aqeous syrup with concentration of α,α-trehalose 68 weight %. After adding 40 ml of 96 % ethanol denatured with 5 % 2-propanol, crystallization proceeds for 10 hours at 5°C. Crystalline α,α-trehalose is isolated by filtration. The filtration cake is washed with 25 ml ethanol and dried in vacuum (50°C, 15 mm Hg) giving 41.4 g α,α-trehalose of purity 99.7 %. Industrial Application Disaccharide a ,α-trehalose produced by the method accor¬ ding to the invention is an important raw material or intermediate in pharmacy, food industry and biochemical research.

Claims: CLAIMS 1. Method for producing crystalline ,α-trehalose by isolation from baker's yeast characterized in that baker's yeast is extracted with ethanol of concentration 70 to 96 volume %, preferably 85 to 96 volume %, the obtained ethanolic extract is freed of solid portion by filtration, concentrated in vacuum to the concentration of α,α-trehalose 2 to 30 weight % and processed by membrane filtration consisting of the ultrafiltration through an ultrafiltration membrane with the separation limit of molecular masses higher than 5000 and, if desirable, of the preceding microfiltration through a microfiltration membrane with mean pore diameter ranging from 0.05 to 5 μm, preferably from 0.05 to 0.15 μm, the obtained clear solution is decolourized with activated charcoal and brought into contact with an ion exchanger in H + cycle and then in OH " cycle, the obtained deminera¬ lized solution is concentrated in vacuum to the concen- tration of 40 to 85 weight %, ethanol is added in the amount of 0.5 to 1.5 parts per 1.0 part of a,α-trehalose and the crystallized α,α-trehalose is isolated and recrystaUized from ethanol after repeated demineraliza¬ tion. 2. Method according to Claim 1, wherein a styrene-divinyl- benzene copolymer with strongly acid sulfo groups is used as the cation exchanger and a styrene-divinyl- benzene copolymer with quaternary dimethylhydroxyethy- lammonium exchanging groups as the anion exchanger. 3. Method according to Claim 1, wherein the continuous ultrafiltration is carried out through an ultrafiltra¬ tion membrane with the separation limit of molecular masses higher than 500 and, if desirable, the preceding microfiltration is carried out through a microfiltration membrane with the mean pore diameter ranging from 0.05 to 5 μm, preferably from 0.05 to 0.15 μ .

Inventors: BLEHA MIROSLAV, JANOUSEK VLADIMIR, PRCHLIK JAROSLAV, SCHAUER JAN, STUCHLIK JIRI, BLEHA, MIROSLAV, JANOUSEK, VLADIMIR, PRCHLIK, JAROSLAV, SCHAUER, JAN, STUCHLIK, JIRI
Applicants: BLEHA MIROSLAV, JANOUSEK VLADIMIR, PRCHLIK JAROSLAV, SCHAUER JAN, STUCHLIK JIRI, USTAV MAKROMOLEKULARNI CHEMIE, VUFB AS, BLEHA, MIROSLAV, JANOUSEK, VLADIMIR, PRCHLIK, JAROSLAV, SCHAUER, JAN, STUCHLIK, JIRI, USTAV MAKROMOLEKULARNI CHEMIE AKADEMIE VED CESKE, VUFB A.S.
Application year: 1994
Main classification: C12P19
IPC codes: C07B63, C07H3, C12P19, C12R1